Drill hole locating apparatus



June 17, 1952 G. F. DE LA MATER DRILL HOLE LOCATING APPARATUS Filed Dec. 2, 1949 3 m n T N N R W O m a m m A 4 f D W F. m E L v. n G

r. g mm F Patented June 17, 1952 F 236003572 DRILLHOLEiBOCZATING'APPARATUS5- (timeit netMimiti esimainegt;new: egiitafiamlieeemliem; 1949;"Serial'Ne; 130325, s ioiaime (01, i isiss):

Thief-invention. relei'fesr= to drill" hole" meeting: apnaratusiandmmie'particularly'toiappaifitusffor isefiective" to accurately loeztethe' positions of which. is" self illuminated so; that it: cm be" ii'sed in operation; simple and'ldiirabie'in construction;

ecbn'omiea rto manufacture; andieas'mte iiser I other objects and: advantageswill; become? apparent from". a: consideration of; the following description and the appended maimein: conjunctlon with the: acconinanyingdimwing:where= Figure" 1 is" a" longitudinal cross s'ectionm view" of the 'apgaravtus in operative position: the'opf posite" sides ofa: diagrammatically" illustrated sheet meted" structure;

Figureffifi's'e top plan view" of a fie; V "enta'ry portion of the apparatus" illilstifltd irif Figure I";

Figureise bottomplan'view'of e mg enmryportion of the ami'aratusflhistiated?Fig'mfeli' Figure is" a transverse erosssection on a somewhat enlarged" settleon" t1i i-1iiie *5 5 OfFiE ure 3-; and

Figil'reti' a" top; plan viewer" anotherfiai T-f menta'i'iy" portion of 5 the: apparatus illustratedin Fig'iirel.

With continued refeiien'ce t6" the" drawing; the" apparatus com rises we units" andKBf; which are" disposed at respectively dpposite i's'ides' of? at sheet metal structure, such" its the diagrem= matically illustrated structure C, for meeting on one side of such" stii'ioture the positionsof drill holes; the l'odatit'ms'. of? Whih are either" known or" selected on" the oppesite- Side of Stinetin.

In" the manuieicture' of stmctur es; suchas "air fiein'es formed" ofoomponentsofsheet aluminum; the rivet 'heles' are normally drilledfi"o'x1"rthein ner side'of-such a structure: ltfi'eqiientlyhep pens, however, that; because of the formation" 2f. from the" inside of the structure because of in'-' terference of components of'theSttiicthiewith the diili'i In these cases: it becomes" necessary ti) arm 3 the holes from" the outside of the strudture and in'such oases-the location of thediill holeson the'outside of the' str'uc'ture mustbeec c-ura'tely determined with reference to the inner" side of the structure;

In locating the positions ofsuoh drill holes-on the outer side'o'f the' structin'e the unit A-tis usedoutside" of the struotiii'eand the unit B is used inside';

The unit comprises 'i an" eleetio-ma'gnet gen-'- 4 era'll y indicated at. Ill" including" a; substantially oylind'ri'oal eorem'ember II' of ma'g'netic materiazlf; suc'h as' iron; having an' annulei" grooveor;

recess I Tthereasfduiid substantially symmetrical with the mid=1ength1ocation of t'he core; This groove inoliides 'an' outer' portion and a radially and-inwardly directed extension narrower than the outer portion; anda high resistanoe mag'netic coil IS is mounted in the narroweninne'r p01- t'ion-of the groove" in the core. The core isprovide'd-with' at cylindi'icalbore I4 which opensto one end ofthe'core and extends substantially'to the opposite end but" is closed at its end adjacentsucnopposite end of the core. 'I' his' bore issubstantiany cda'X-iai with a-1ongitudina1'center' line ofthe core and with the magnetic coil I 3;

A needle I Hfofthin magnetic material; such as shimsteeL is disposed the bore- I4 and' extendslongitudinally thereof 1 Thign'eedle'is" provided at:

side of'the jewel I6 to" provide it jewel bearing" fer 'th'e n'e'edl'. This s'taff ismounted in a; sleeve IB disposed in the bore llandheldin properposi tioir longitu'dinztlly-"oii the" bore by- 21' spacer sleeve II8 one-end of which engages th closed end of the-bore end the other endof which providesa bearingfor the adjacent end of the bearing mounted 1n" thes-l'eeve- I 8.

A cylindrical housing I 9 surrounds the core I 'I' of-theele'ctio -inagntmid eX-tendsbeyoridthe end 61 the ante w-wmeh-me h'or'e I 4" opens, and a; air:- cums Block 2 0 of nonmagnetic material" such as: ai'uminum, ismountea on this end of the core midi-is held'th'eron by the housing I 9"; This block has its ehd onpositethe-oore II conc'avely-sheped 82ml Ii'rOVidEG -With" a centre-11 located bore 21' Whieiiextends thrtthiouh siibstantially in alignment with the bore I4 in the magnet coreprovided in the end of the block 26 adjacent the core II and extends from th bore 2! to the exterior of the block. The housing i9 is provided with an aperture 23 registering with the outer end of this recess 22. A crystal 24 in the shape of a circular disc, is mounted in the end of the bore 2i in the block 22 remote from the magnet core and an indentation or dot 25 is provided on the under or inner surface of this crystal at the center thereof and constitutes an indicating mark for the instrument. A slender pointer 25 is attached to the needle and extends from the needle to a location cloesly adjacent the under or inner surface of the crystal and this pointer has on its end adjacent the crystal a colored head which cooperates with the indicating dot 25 to indicate the position of the needle relative to the bor $4 in which the needle is pivotally supported.

A battery case 27 is secured at one end of the housing I9 in position to inclose the aperture 23 in the housing and flash light battery cells 28 and 29 are contained in this case.

A flanged disc 3G is secured transversely in the battery case adjacent the housing l9 and a bracket 3i secured at one end to this disc extends toward the aperture 23 in the housing. A bulb socket 32 is mounted on the end of bracket 3! adjacent the housing I?! and a light bulb 33 carried by this socket is positioned to transmit light through the recess 22 into the bore 2| to illuminate the pointer 25 and indicating dot 25.

A switch is carried by the flanged disc 3c and comprises a first resilient switch arm 34 extend ing from the disc toward the housing I?) and a second resilient arm 35 also extending from the disc 33 toward the housing IS in spaced relationship to the arm 34. Conductors 36 and 3! connect the insulated terminal 43 carried by switch arm 34 to the coil l3 and bulb socket 32 respectively. the bracket 3! and the coil is grounded through the conductor 38. The battery including the cells 28 and 29 is grounded at one end to the battery case and is in contact at its opposite end with one end of the switch arm 35 which switch arm is electrically insulated from the supporting disc 30. The arm 35 is bent at its opposite and toward the contact 40 carried by switch arm 34 and a thumb button 39 mounted on switch arm bring the bent end of arm 35 into engagement with contact 49 thus establishing parallel en ergizing circuits for the bulb 33 and coil I3.

The coil 13 is a high resistance coil, a resist ance of approximately 80 ohms having been found to provide satisfactory results in use, and bulb 33 is an ordinary flash light bulb, so the flash light battery cells 28 and 25 will last for a satisfactory period of use.

When the coil 13 is energized it establishes a. magnetic field which symmetric permeates the core ii and o no longitudi nal center line of the bore 54. This magnetic field temporarily magnetizes the needle and prevents any reversal of polarity of the needle while, at the same time, urging the needle to a position in which it is substantialy in alignment with the longitudinal center line of the bore. This position of the needle is indicated by a substantial coincidence of the head of the pointer 26 with the indicating dot 25 and any deflection of the needle from this position is indicated by a departure of the pointer head from the indicating dot.

The unit B comprises an elongated perma- The socket is grounded through is operative manually depressed, to

nent magnet M which may be of cylindrical form and has one end reduced to provide a nose 42. The polarity at the nose 42 is opposite to the polarity of the end of the needle adjacent the closed end of the bore l4.

This magnet is mounted in a cylindrical housing 43 considerably larger than the magnet and is held in centered relationship in the housing by a bushing 44 of electrically insulative, nonmagnetic material which surrounds the magnet within the housing. A handle 45, which may be of elongated. cylindrical form, is secured at one end to the housing 53 and projects radially thcrefrom. I T

In using the apparatus the magnet H is positioned at the inner side of the structure C with. its nose 42 at the desired location of the drill hole. The unit A is then placed against the outer side of the structure with the electromagnet ll at the estimated location of the hole on the outer side of the structure The switch is then closed by depressing the thumb button 39 and, if the electromagnet is not properly located the needle li4will be deflected by the magnet 4i from its normal or neutral position substantially in ali nment with the longitudinal center line of the bore I4, the direction in which the adjacent end of the needle is displaced from the nose of the permanent magnet 4! being indicated by the direction in which the head of the pointer 25 is displaced from the indicating dot 25. The electromagnet is then moved over the outer surface of the structure until the head of the pointer coincides with the location of the indicating dot. The needle H4 will then be in alignment with the longitudinal center line of the permanent magnet 25 and with the longi" tudinal center line of the bore l4 and theend of the needle adjacent the structure C will be directly over the drill hole location.

A flat pad of absorbent material is secured to the end of the electromagnetic core [I opposite the block 20 and a small aperture 41 in this pad is centered on the longitudinal center line of the bore [4.

The pad is impregnated with a suitable ink or other marking material and when the location of the drill hole has been determined, as explained above, the pad 45 is pressed firmly against the adjacent surface of the structure to make a mark thereon. The aperture 47 will. provide in this mark. a small dot indicating the location of the drill hole center.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The pres ent embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come with in the meaning and range of equivalency of the claims are intended to be embraced therein.

I claim:

1. Drill hole locating apparatus comprising an electro-magnet having a bore therein, a needle disposed in said bore and pivotally supported substantially at its mid length location in the magnetic field of said .electro-magnet, a crystal supported at a location spaced from one end of the bore in said electro-magnet and having an indicating dot thereon, a pointer extending from said needle substantially to the adjacent surface of said crystal and cooperating with said dot to indicate the position of said needle relative to said bore, a battery case secured to said electromagnet, a lamp bulb carried by said battery case for illuminating said crystal and said pointer, a battery in said case, and conductor means providing an energizing circuit from said battery to said electro-magnet and said lamp bulb.

2. Drill hole locating apparatus comprising an electro-magnet having a longitudinally extending bore therein, a needle pivotally mounted in said bore to extend longitudinally thereof and urged by the magnetic field of said electro-magnet to a position in which it is substantially in alignment with the longitudinal center line of said bore, means indicating deflection of said needle from said position, a battery case secured to said electro-magnet, a battery in said battery case, and means providing an energizing circuit from said battery to said electromagnet.

3. Drill hole locating apparatus comprising an electro-magnet having a bore therein, a needle disposed in said bore and pivotally supported substantially at its mid-length location in the mag netic field of said electro-magnet, a crystal supported at a location spaced from one end of the bore in said electro-magnet and having an indicating dot thereon, a pointer extending from said needle substantially to the adjacent surface of said crystal and cooperating with said dot to indicate the position of said needle relative to said bore, a battery case secured to said electro-magnet, a lamp bulb carried by said battery case for illuminating said crystal and said pointer, a battery in said case, conductor means providing an energizing circuit from said battery to said electro-ma-gnet and said lamp bulb, and marking means carried by the eleotro-magnet and engageable on the surface of the structure to physically indicate on the surface the point of alignment of the needle with the permanent magnet.

4. In an apparatus for locating through an opaque structure a permanent magnet on one side thereof, an electro-magnet having a bore therein, a needle pivotally housed in said bore for swinging movement transversely of the bore, a crystal supported in alignment with said bore and disposed transversely of the needle, said crystal having an indication mark formed thereon, a pointer extending from one end of the needle and arranged at right angles to the pivot axis of the needle, said pointer terminating adjacent to the crystal and cooperating with the indication mark to indicate the aligned position of the needle relative to the cooperative magnet on the oppo site side of the structure, a housing affixed to the electro-magnet, illuminating means in said housing for illuminating the needle and crystal, and a source of electrical energy in said housing for the illuminating means and the electro-magnet.

5. In an apparatus for locating through an opaque structure a permanent magnet on one side thereof, an electro-magnet having a bore therein, a needle pivotally housed in said bore for swinging movement transversely of the bore,

a crystal supported in aligmnent with said bore and disposed transversely of the needle, said crystal having an indication mark formed thereon, a pointer extending from one end of the needle and arranged at right angles to the pivot axis of the needle, said pointer terminating adjacent to the crystal and cooperating with the indication mark to indicate the aligned position of the needle relative to the cooperative magnet on the opposite side of the structure, a housing affixed to the electro-magnet, illuminating means in said housing for illuminating the needle and crystal, a source of electrical energy in said housing for the illuminating means and the electro-magnet, and marking means carried by the electro-magnet at the end thereof opposite to the crystal, said marking means being engageable on the surface of the structure to physically indicate on the surface the point at which the needle is directed.

6. In an apparatus for locating through an opaque structure a permanent magnet on one side thereof, an electro-magnet having a bore therein, a needle pivotally housed in said bore for swinging movement transversely of the bore, a crystal supported in alignment with said bore and disposed transversely of the needle, said crystal having an indication mark formed thereon, a pointer extending from one end of the needle and arranged at right angles to the pivot axis of the needle, said pointer terminating adjacent to the crystal and cooperating with the indication mark to indicate the aligned position of the needle relative to the cooperative magnet on the opposite side of the structure, a housing aflixed to the electro-magnet, illuminating means in said housing for illuminating the needle and crystal, a source of electrical energy in said housing for the illuminating means and the electro-magnet, and marking means carried by the electro-magnet at the end thereof opposite to the crystal, said marking means being engageable on the surface of the structure to physically indicate on the surface the point at which the needle is directed, said marking means including an inking pad having an opening therein alignable with the needle when the pointer on the needle is in coincidence with the indication mark.

GALE F. DE LA MATER.

REFERENCES CITED The following references are of record in the of this patent:

UNITED STATES PATENTS Number Name Date 1,940,521 Acosta Dec. 19, 1933 1,971,189 Leibing Aug. 21, 1934 2,346,773 McBride et al Apr. 18, 1944 FOREIGN PATENTS Number Country Date 681,671 France Feb. 3, 1930 

